Java 如何使用此方法从二维阵列获取数据？

我得到了一个返回二维对象数组的方法。如何使用下面给出的方法从对象数组中获取数据，并将其放入表或标签中以查看其中存储的数据？这是我尝试过但没有成功的方法：

Object[][] diffs = comp.getDifferences(comp.getName());
for(Object diff : diffs){

    table.addItem(diff);
}

这就是我得到的方法：

public Object[][] getDifferences(String table) {
    List<Tuple<Object, Object>> difference = differences.get(table);
    Object[][] array = new Object[difference.size()][2];

    for (int i = 0; i < array.length; i++) {
        array[i][0] = difference.get(i).item1();
        array[i][1] = difference.get(i).item2();
    }

    return array;
}

下面是整个Comparecomp类：

public class Compare implements Serializable {
private String name;
private Map<String, List<Tuple<Object, Object>>> differences = new HashMap<String, List<Tuple<Object, Object>>>();

public Compare(String name) {
    this.name = name;
}

public Compare(byte[] bytes) throws IOException, ClassNotFoundException {
    ByteArrayInputStream bis = new ByteArrayInputStream(bytes);
    ObjectInput ois = new ObjectInputStream(bis);

    Compare compare = (Compare)ois.readObject();
    this.name = compare.name;
    this.differences = compare.differences;

    bis.close();
    ois.close();
}

public String getName() {
    return name;
}

public boolean addDifference(String table, Object control, Object test) {
    if (!differences.containsKey(table)) {
        differences.put(table, new ArrayList<Tuple<Object, Object>>());
    }

    differences.get(table).add(new Tuple<Object, Object>(control, test));

    return true;
}

public Object[][] getDifferences(String table) {
    List<Tuple<Object, Object>> difference = differences.get(table);
    Object[][] array = new Object[difference.size()][2];

    for (int i = 0; i < array.length; i++) {
        array[i][0] = difference.get(i).item1();
        array[i][1] = difference.get(i).item2();
    }

    return array;
}

public byte[] toBytes() throws IOException {
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    ObjectOutput oos = new ObjectOutputStream(bos);

    oos.writeObject(this);
    oos.flush();

    byte[] bytes = bos.toByteArray();

    bos.close();
    oos.close();

    return bytes;
}

private class Tuple<X, Y> implements Serializable {
    private final X x;
    private final Y y;

    public Tuple(X x, Y y) {
        this.x = x;
        this.y = y;
    }

    public X item1() {
        return this.x;
    }

    public Y item2() {
        return this.y;
    }
}

public static void main(String[] args) throws FileNotFoundException, IOException, ClassNotFoundException {
    Compare foo = new Compare("Test Compare");
    foo.addDifference("AGREEMENT", 89, 90);
    foo.addDifference("AGREEMENT", "foo", "bar");
    foo.addDifference("ACCOUNT", 123, "Dog");

    ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(new File("C:\\Users\\uttbm01\\Documents\\Export\\foo.cmp")));
    oos.writeObject(foo);
    oos.close();

    ObjectInputStream ois = new ObjectInputStream(new FileInputStream(new File("C:\\Users\\uttbm01\\Documents\\Export\\foo.cmp")));
    Compare bar = (Compare)ois.readObject();
    ois.close();

    System.out.println();
}

---

}

我不会通读你所有的代码。我可以理解为什么在你说的行中会出现一个NullPointerException，原因是in difference.size difference是null，所以你在对null调用一个方法。这很可能是因为我查询的映射（差异）没有将表作为键的映射。不太可能的解释是键在那里，但与它关联的值为null

---

如果您确定键值对应该具有非空值，则需要检查将其放入其中的代码，以了解为什么没有。另一方面，如果您不想保证它存在，那么应该使用If-else对差异进行空检查。如果差异为null，例如，您可以从方法返回新对象[0][]。

这是要比较什么？它是在比较一个字符串和另一个字符串吗？您预期的结果是什么？该方法没有返回两个数组。它返回一个二维数组。您可以通过提供行和列索引来访问其成员-例如，diff[0][0]和diff[0][1]。该方法会从差异列表中提取名称元素。然后将这些提取的名称添加到一个双数组中，通过调用Array[i][0]==Array[i][1]并比较它们是否是相同的元素，可以访问每个元素。您可以调用==或.equal来比较两个元素。哇，问问题已经被否决了吗？令人惊叹的感谢那些试图在否决投票前提供某种反馈的评论者。安迪·托马斯和朱尼尔，谢谢。你们说得对。你的回答指引了我正确的方向。此外，我只想列出所有的差异，并打印到表格或标签上，或任何东西。仅此而已。不需要做任何比较。我只是想看看那里有什么。比较已经完成，差异存储在comp中。

Object[][] array = new Object[difference.size()][2];

public class Compare implements Serializable {
private String name;
private Map<String, List<Tuple<Object, Object>>> differences = new HashMap<String, List<Tuple<Object, Object>>>();

public Compare(String name) {
    this.name = name;
}

public Compare(byte[] bytes) throws IOException, ClassNotFoundException {
    ByteArrayInputStream bis = new ByteArrayInputStream(bytes);
    ObjectInput ois = new ObjectInputStream(bis);

    Compare compare = (Compare)ois.readObject();
    this.name = compare.name;
    this.differences = compare.differences;

    bis.close();
    ois.close();
}

public String getName() {
    return name;
}

public boolean addDifference(String table, Object control, Object test) {
    if (!differences.containsKey(table)) {
        differences.put(table, new ArrayList<Tuple<Object, Object>>());
    }

    differences.get(table).add(new Tuple<Object, Object>(control, test));

    return true;
}

public Object[][] getDifferences(String table) {
    List<Tuple<Object, Object>> difference = differences.get(table);
    Object[][] array = new Object[difference.size()][2];

    for (int i = 0; i < array.length; i++) {
        array[i][0] = difference.get(i).item1();
        array[i][1] = difference.get(i).item2();
    }

    return array;
}

public byte[] toBytes() throws IOException {
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    ObjectOutput oos = new ObjectOutputStream(bos);

    oos.writeObject(this);
    oos.flush();

    byte[] bytes = bos.toByteArray();

    bos.close();
    oos.close();

    return bytes;
}

private class Tuple<X, Y> implements Serializable {
    private final X x;
    private final Y y;

    public Tuple(X x, Y y) {
        this.x = x;
        this.y = y;
    }

    public X item1() {
        return this.x;
    }

    public Y item2() {
        return this.y;
    }
}

public static void main(String[] args) throws FileNotFoundException, IOException, ClassNotFoundException {
    Compare foo = new Compare("Test Compare");
    foo.addDifference("AGREEMENT", 89, 90);
    foo.addDifference("AGREEMENT", "foo", "bar");
    foo.addDifference("ACCOUNT", 123, "Dog");

    ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(new File("C:\\Users\\uttbm01\\Documents\\Export\\foo.cmp")));
    oos.writeObject(foo);
    oos.close();

    ObjectInputStream ois = new ObjectInputStream(new FileInputStream(new File("C:\\Users\\uttbm01\\Documents\\Export\\foo.cmp")));
    Compare bar = (Compare)ois.readObject();
    ois.close();

    System.out.println();
}